POT 


Univ .  of 

5  3 

H.  J.  VANCUEAV^  H»zsr 


11.  Library 


ILLINOIS 


un,versity  or 
Urban*,  ILUNOI^ 


UNIVERSITY  OF  ILLINOIS 


DEPARTMENT  OF  ENTOMOLOGY 


ENTOMOLOGY  FOUR 


INTRODUCTION  TO  ECONOMIC  ENTOMOLOGY 


SYLLABUS  OF  LECTURES 


BY 


J.  W.  FOLSOM,  SCO. 


1915 


%  V  O) 


SYLLABUS  OF  LECTURES 

INTRODUCTION 

Importance  of  Economic  Entomology.— Losses  due  to  insect 
pests.  Work  of  the  U.  S.  Bureau  of  Entomology;  of  state  ento¬ 
mologists  and  state  experiment  stations.  State  entomological 
work  in  Illinois. 

The  Place  of  Insects  in  the  Animal  Kingdom. — Characters  of 
Arthropoda :  Symmetry,  segmentation,  appendages,  skeleton, 
etc.  The  more  important  distinctions  between  the  six  classes  of 
arthropods. 

Definition  of  an  Insect. — Head :  eyes,  antennae,  mouth  parts. 
Thorax:  segments,  legs,  wings.  Abdomen:  segments,  appen¬ 
dages.  Spiracles.  Metamorphosis. 

Metamorphoses. — Direct,  or  incomplete,  metamorphosis  (ex¬ 
amples  :  grasshopper,  squash-bug) ;  nymph,  imago.  Indirect,  or 
complete,  metamorphosis  (examples:  butterflies,  beetles,  flies, 
bees) ;  larva,  pupa,  imago,  caterpillar,  chrysalis,  grub,  maggot, 
puparium.  Ecdysis,  or  molting. 

Outline  of  the  Structure  of  an  Insect. — Characteristics  of  the 
exoskeleton;  chitin.  Nervous  and  circulatory  systems.  Fat  body. 
Digestive  system.  Types  of  mouth-parts  (mandibulate  and  suc¬ 
torial).  The  use  of  insecticides  as  determined  by  the  feeding 
habits  of  an  insect.  Stomach  poisons  and  contact  poisons.  Re¬ 
spiratory  system  in  its  relation  to  contact  poisons. 

FRUIT  INSECTS 
Greater  Peach-tree  Borer 
Sanninoidea  exitiosa  Say 

Importance. —  - .  Distribution. — A  native  of  North 

America.  In  almost  all  states  east  of  the  Rocky  Mountains;  in 
~  parts  of  Canada.  Means  of  distribution,  natural  and  artificial. 

Food  Plants. — Peach,  plum,  cherry,  apricot,  nectarine,  prune, 
^flowering  almond,  azalea,  wild  cherry. 

Injuries. — Appearance  of  infested  tree.  Burrows  of  the  in¬ 
sect.  Effects  upon  the  tree. 
r  Descriptions. — Egg,  larva,  pupa,  imagines. 

Life  History  and  Habits. — One  annual  generation.  Hiberna¬ 
tion.  Pupation.  Emergence  of  adults.  Adults  on  the  wing 
mostly  in  July  and  August  in  Illinois.  Habits  of  adults.  Ovipo- 
sition.  Habits  of  young  larvae. 


2 


Natural  Enemies. — Braconids,  chalcids,  ichneumonids. 

Control. — Digging-out.  Mounding.  Repellents:  tobacco, 
Hale’s  wash,  gas-tar.  Banding. 

References. — Bull.  176,  Cornell  Experiment  Station;  Bull. 
128,  N.  J.  Experiment  Station;  Girc.  54,  U.  S.  Division  of  En¬ 
tomology. 

Lesser  Peach-tree  Borer 
Synanthedon  pictipes  G.  &  R. 

Distribution. — Native  of  North  America.  Canada  to  Florida; 
westward  into  California. 

Food  Plants. — Cultivated  and  wild  plums  and  cherries, 
peach,  chestnut,  black-knot  fungus  of  plum  and  cherry,  etc. 

Injuries. — Said  to  attack  none  but  injured  trees.  Injuries 
compared  with  those  of  S.  exitiosa. 

Description. — Eggs,  larvae,  pupae,  and  adults  compared  with 
those  of  S.  exitiosa.  (Often  confused  with  S.  exitiosa.) 

Life  History  and  Habits. — Two  generations.  Hibernation. 
Moths  emerge  in  May  and  June  (Illinois).  Egg  period  about  ten 
days;  pupal  period  three  to  four  weeks. 

Control. — Digging-out.  Repellents. 

Reference. — Bull.  68,  Pt.  4,  U.  S.  Bureau  of  Entomology. 

Codling-moth 
Carpocapsa  pomonella  L. 

Economic  Importance. —  - .  Distribution. — Europe, 

Siberia,  W.  Central  Asia,  South  Africa,  New  Zealand,  Tasmania, 
Brazil,  United  States,  Canada.  Probably  introduced  into  United 
States  from  Europe  with  apples  or  pears.  Commercial  distri¬ 
bution. 

Food  Plants. — Chiefly  apple  and  pear;  also  quince,  plum, 
peach,  apricot,  cherry,  prune,  crab  apple,  red  haw,  and  thin- 
shelled  walnuts. 

Injuries. — Effects  on  earlier  and  on  later  maturing  varieties. 
Wormy  apples.  Windfalls. 

Descriptions. — Egg,  larva,  pupa,  imago. 

Life  History  and  Habits. — Two  full  generations  and  a  par¬ 
tial  third,  in  Illinois.  Hibernation  as  a  larva.  Pupal  period  in 
spring  two  or  three  weeks.  Moths  in  May  (Illinois).  Habits  of 
the  moth.  Oviposition.  Egg  period,  four  to  ten  days.  Feeding 
habits  of  young  larva.  Larval  period  twelve  to  thirty  days.  Sec¬ 
ond  generation  of  moths  winged  in  July  and  early  August  (Illi- 


3 


nois).  Habits  of  the  larvae.  History  of  the  partial  third  genera¬ 
tion  in  Illinois. 

Natural  Enemies. — Parasitic  insects.  Woodpeckers. 

Control. — Banding.  Screening  of  storerooms.  Destruction 
of  windfalls;  use  of  pigs  for  this  purpose.  Spraying:  impor¬ 
tance;  experiments  in  Illinois.  Paris  green,  1  lb.  to  150  gallons 
water,  with  2  lbs.  of  freshly  slaked  lime.  Paris  green  with 
Bordeaux  mixture.  Arsenate  of  lead,  1  lb.  to  50  gallons  water, 
to  replace  Paris  green.  Advantages  of  arsenate  of  lead.  Rules 
for  spraying.  Relation  of  these  rules  to  the  habits  of  the  insect 
Experiments  in  Illinois  on  spraying  for  the  second  generation 
of  codling-moth.  Cost  of  spraying.  Little  if  any  danger  of 
arsenical  poisoning  from  sprayed  apples. 

References. — Bull.  41,  U.  S.  Division  of  Entomology;  Bull. 
142,  Cornell  Experiment  Station;  Bull.  114,  Illinois  Experiment 
Station. 

Plum-curculio 
Conotrachelus  nenuphar  Hbst. 

Economic  Importance. —  - .  Distribution. — Native  to 

North  America.  Canada  to  Gulf  of  Mexico;  Atlantic  to  the  one 
hundredth  meridian. 

Food  Plants. — Chiefly  plum,  cherry,  peach,  apple ;  and  pear, 
quince,  apricot,  nectarine,  prune,  persimmon;  also  wild  plum, 
wild  crabs,  and  haws.  Black-knot  of  plum  and  cherry. 

Injuries. — Work  of  beetle  on  buds,  leaves,  and  bark  of  fruit 
trees.  Effects  of  food  punctures  on  young  fruit  and  on  old  fruit. 
Effects  on  plums,  cherries,  peaches,  and  apples  compared.  Egg 
punctures  and  crescent-cuts.  Failure  of  larval  development  in 
fruit  that  does  not  fall,  or  that  does  not  decay.  Injury  in  apple 
orchards  in  Illinois. 

Descriptions. — Egg,  larva,  pupa,  imago. 

Life  History  and  Habits. — One  annual  generation.  Hiber¬ 
nates  as  adult.  Beetles  appear  the  last  of  April  or  early  in  May. 
Process  of  opposition.  Egg  period,  four  to  seven  days.  Crush¬ 
ing  of  eggs  or  larvae  by  the  growth  of  the  pulp.  Larval  period, 
about  three  weeks.  Average  period  as  larva  and  pupa  in  the 
soil,  four  weeks.  Ninety-three  percent  pupate  within  two  inches 
of  surface  of  ground.  Beetles  issue  mostly  in  July  and  August. 
Habits  of  the  beetles  in  summer. 

Natural  Enemies. — Parasitic  insects.  Poultry. 

Control. — Trapping  on  the  ground.  Destruction  of  wind¬ 
falls  by  use  of  hogs.  Result  of  raking  fallen  fruit  into  the  sun- 


4 


light.  Control  in  apple  orchard  by  surface  cultivation  with  disk 
or  harrow,  at  intervals  between  July  10  and  August  10.  Jarring: 
description  of  process;  effectiveness;  cost.  Spraying:  results  as 
compared  with  those  of  jarring.  Forbes’  experiments  in  1885. 
Arsenate  of  lead  2%  lbs.  to  50  gallons  water ;  three  applications ; 
benefit  ;  cost,  17  cents  per  tree.  Self-boiled  lime-sulphur  wash. 

References. — Bull.  98  and  108,  Illinois  Experiment  Station; 
Girc.  73  and  120,  U.  S.  Bureau  of  Entomology;  Bull.  103,  U.  S. 
Bureau  of  Entomology;  Bull.  21,  Mo.  State  Fruit  Experiment  Sta¬ 
tion;  Farmers’  Bull.  440,  U.  S.  Department  of  Agriculture. 

Apple-curculio 

Anthonomus  quadrigibbus  Say 

Importance. —  - .  Distribution. — Native  to  North 

America. 

Food  Plants. — Wild  crab-apples,  hawthorns,  cultivated  ap¬ 
ples. 

Injuries. — Food  punctures  and  egg  punctures.  Deformities 
caused  by  the  punctures. 

Descriptions. — Compare  with  plum-curculio  in  its  several 
stages. 

Life  History  and  Habits. — Hibernates  as  a  beetle..  Beetles 
appear  on  trees  early  in  May.  Oviposition.  Egg  period,  four 
days.  Eggs  laid  from  last  of  May  to  last  of  July.  Larval  period, 
three  weeks;  pupal,  one  week.  Pupation  inside  the  apple.  Habits 
of  the  beetles.  One  annual  generation. 

Control. — Experiments  with  arsenicals. 

Reference. — Bull.  98,  Illinois  Experiment  Station. 

Round-headed  Borer 
Saperda  Candida  Fab. 

Distribution. — Native  to  North  America.  In  most  states  east 
of  Rocky  Mountains ;  Oregon,  Canada. 

Food  Plants . — Wild  crab,  mountain  ash,  hawthorn,  apple, 
pear,  quince. 

Injuries. — Weakening  and  death  of  affected  trees. 

Descriptions. — Egg,  larva,  pupa,  imago. 

Life  History  and  Habits. — Three-year  cycle.  Eggs  on  bark 
of  trunk;  period,  two  weeks.  Feeding  habits  of  larva;  length  of 
life.  Pupation;  period,  three  weeks.  Exit  of  beetle.  Habits  of 
beetles:  appear  in  May  and  June;  nocturnal;  oviposition,  June 
to  September. 


5 


Natural  Enemies. — Braconidae.  Woodpeckers. 

Control. — Gutting  out,  in  August  and  September,  or  May. 
Barriers.  Repellent  washes:  soft  soap  and  caustic  potash  or 
washing  soda;  fish-oil  soap;  white  lead  and  linseed  oil. 

References. — Girc.  32,  U.  S.  Division  of  Entomology;  Bull. 
74,  N.  Y.  State  Museum. 

Flat-headed  Borer 
Chrysobothris  femorata  Fab. 

Distribution. — Almost  the  entire  United  States;  southern 
Canada.  Native  of  North  America. 

Food  Plants. — Fruit  trees.  Many  common  shade  and  forest 
trees. 

Injuries. — Prefers  weakened  or  dying  trees.  Injury  to  nurs¬ 
ery  stock. 

Descriptions. — Comparisons  with  S.  Candida. 

Life  History  and  Habits. — One-year  cycle.  Beetles  in  May, 
June,  July;  diurnal.  Eggs  on  trunk  and  larger  limbs.  Larval 
habits.  Pupation ;  period,  three  weeks.  Hibernates  as  a  larva. 

Natural  Enemies. — Braconidae,  Ghalcididae,  Ichneumonid®. 
Ants.  Woodpeckers. 

Control. — Gutting-out.  Scalding.  Alkaline  washes,  as  for 
S.  Candida.  Trapping. 

Reference. — Girc.  32,  U.  S.  Division  of  Entomology. 

Shot-hole  Borer 
Scolytus  rugulosus  Ratz. 

Importance. —  - .  Distribution. — Introduced  from 

Europe.  Massachusetts  to  Kansas ;  Michigan  to  Alabama.  South¬ 
ern  Canada.  On  nursery  stock. 

Food  Plants. — Plum,  peach,  and  apple,  especially.  All  stone 
fruits,  pear,  quince,  hawthorn,  mountain  ash. 

Injuries. — Attacks  unhealthy  trees  as  a  rule.  Withered 
leaves,  shriveled  bark,  death  of  limbs.  Destruction  of  cambium 
layer. 

Descriptions. — Egg,  larva,  pupa,  imago. 

Life  History  and  Habits. — Winters  as  larva,  in  outer  part  of 
sapwood  or  in  inner  bark.  Pupates  in  spring,  beetles  emerging 
in  April.  Habits  of  beetles.  Egg-laying  habits.  Larval  habits. 
Pupation.  Exit  of  adults.  Three  or  four  annual  generations; 
cycle  about  five  weeks  in  summer.  Eggs  in  September  (Illinois). 

Natural  Enemies. — Ghalcids.  Woodpeckers. 


6 


Control. — Trimming  and  burning.  Kerosene.  Washes :  1  lb. 
fish-oil  soap  to  2  gallons  water,  applied  late  in  March  or  early  in 
April;  one  gallon  soft  soap,  one  pint  crude  carbolic  acid,  eight 
gallons  water. 

References. — 17th  Report,  State  Entomologist,  Illinois;  Girc. 
29,  U.  S.  Division  of  Entomology;  Bull.  44,  Mo.  Experiment  Sta¬ 
tion;  Bull.  180,  N.  Y.  Experiment  Station  (Geneva). 

Woolly  Louse  op  Apple 
Schizoneura  lanigera  Hausm. 

Importance. —  - .  Distribution. — Western  Europe, 

South  Africa,  Australia,  India,  Chile,  North  America.  Most  in¬ 
jurious  in  latitude  of  Ohio  valley.  Distributed  widely  on  nursery 
stock. 

Food  Plants. — Apple,  alternating  with  elm.  Pear,  quince, 
wild  haws,  wild  crab-apple.  Some  varieties  of  apple  said  to  be 
immune  (northern  spy,  golden  pippin,  etc.). 

Injuries. — Aerial  forms,  on  wounds,  scars,  or  water  shoots; 
often  cause  leaves  to  fall.  Subterranean  forms,  about  crown  of 
plant;  cause  galls  and  often  kill  young  trees. 

Descriptions. — Egg,  viviparous  females  (winged  or  wing¬ 
less),  oviparous  females,  males.  Waxy  secretion. 

Life  History  and  Habits. — The  oviparous  females  are  said  to 
lay  but  one  winter  egg.  Migration  in  autumn  from  apple  to  elm. 
Eggs  on  elm  or  on  apple.  Viviparous  females  may  survive  win¬ 
ter  on  branches  or  roots,  in  the  South.  Migration  of  third  gener¬ 
ation  in  spring  from  elm  to  apple. 

Natural  Enemies. — Chalcididae,  Syrphidae,  Goccinellidee, 
Chrysopidae. 

Control. — Bisulphid  of  carbon  dangerous  to  plants.  To¬ 
bacco  dust  in  furrows  in  which  trees  are  to  be  planted;  in  fur¬ 
rows  beside  rows  of  trees.  Treatment  of  old  trees  with  tobacco 
dust.  Kerosene-soap  emulsion  (7  percent),  tobacco  decoction, 
fish-oil  soaps  (1  lb.  to  6  gal.  water),  for  aerial  forms.  Gasoline 
blast  lamp.  Hot  water.  Gas-lime. 

References. — Bull.  35,  Mo.  Experiment  Station;  Bull.  80,  Ky. 
Experiment  Station;  Bull.  17,  U.  S.  Division  of  Entomology;  Girc. 
20,  U.  S.  Bureau  of  Entomology;  Bull.  217,  Me.  Experiment 
Station. 

Pear-slug 

Eriocampoides  limacina  Retz. 

Importance. —  - .  Distribution.  —  Europe.  North 


7 


America.  Carried  in  soil  about  roots  of  plants. 

Food  Plants. — Pear,  plum,  cherry,  quince. 

Injuries. — Skeletonizes  leaves,  which  turn  brown  and  die. 
Occasionally  kills  a  tree. 

Descriptions. — Egg,  larva,  pupa,  imago. 

Life  History  and  Habits. — Larva  hibernates  in  the  soil,  pupat¬ 
ing  in  spring.  Adults  issue  when  pear  leaves  are  expanding. 
Process  of  oviposition.  Egg  period,  two  weeks.  Sensitiveness  of 
eggs  and  larvae  to  cold  wet  weather.  Larval  period,  three  or  four 
weeks;  pupal  period,  two  weeks.  Injury  in  Illinois  in  June,  July, 
August,  September.  Two  generations.  Second  generation  of 
slugs  full  grown  in  September  and  October. 

Control. — Arsenical  sprays.  Whale-oil  soap,  1  lb.  to  4  gals, 
water;  or  simple  soap  solution,  y2  lb.  to  1  gal.  water.  Hellebore, 
1  oz.  to  2  gals,  water;  or  dry,  with  5  to  10  parts  of  flour.  Effect 
of  heavy  rains.  “Black  Leaf  40”,  1  gal.  to  1000  gals,  water. 

Reference. — Circ.  26,  U.  S.  Division  of  Entomology. 

Spring  Canker-worm 
Paleacrita  vernata  Peck 

Importance. —  - .  Distribution. — New  England  to 

Mississippi  valley.  Spreads  slowly,  by  natural  means.  Young 
larvae  sometimes  carried  by  strong  winds. 

Food  Plants. — Apple,  elm,  cherry,  plum,  and  a  few  other 
plants. 

Injuries. — Larvae  skeletonize  leaves,  diminishing  the  vitality 
of  a  tree,  and  sometimes  killing  it,  by  repeated  defoliations. 

Descriptions. — Egg,  larva,  pupa,  imago. 

Life  History  and  Habits. — One  annual  generation.  Hiber¬ 
nates  as  a  pupa  in  the  soil.  Moths  emerge  in  early  spring,  the 
males  preceding  the  females;  emerge  in  Illinois  March  7  to  April 
7.  Females  crawl  up  trunks  of  trees  to  lay  their  eggs.  Ovi¬ 
position.  Eggs  hatch  as  young  leaves  push  from  bud.  Larval 
period,  three  to  four  weeks.  Larval  habits. 

Control. — Banding:  tanglefoot,  coal-tar,  printers’  ink,  sor¬ 
ghum  molasses  and  flour.  Kill  eggs  laid  below  the  band.  Use  of 
arsenicals.  Jarring.  Cultivation. 

References. — Third  Report,  U.  S.  Entomological  Commis¬ 
sion;  Bull.  44,  85,  N.  H.  Experiment  Station;  Bull.  68,  Pt.  2,  U.  S. 
Bureau  of  Entomology. 


8 


Scurfy  Scale 
Chionaspis  furfura  Fitch 

Distribution. — A  native  of  North  America.  Occurs  through¬ 
out  the  United  States  and  in  most  parts  of  Canada. 

Food  Plants. — Thirty-six  species  listed,  the  most  important 
being  apple,  pear,  plum,  and  cherry.  Also  many  other  fruit  trees, 
wild  or  cultivated ;  currant,  gooseberry,  ash,  hickory. 

Injuries. — Trees  are  stunted  by  this  scale,  particularly  young 
trees.  Occasionally  on  leaves  or  fruit.  Reddish  discoloration  of 
green  tissue. 

Descriptions. — Male  and  female  scales.  Adult  males  and  fe¬ 
males.  Larvae.  Eggs. 

Life  History  and  Habits. — One  annual  generation  in  North¬ 
ern  States.  Females  die  at  approach  of  winter.  Eggs  under 
female  scales;  purplish;  average  number,  66.  Hatch  early  in 
June  (Illinois).  Males  issue  in  September.  Eggs  laid  in  late 
September  or  early  October  (Illinois). 

Natural  Enemies. — Mites.  Chalcididae.  Coccinellidae. 

Control. — Lime-sulphur  wash,  applied  to  dormant  trees. 
Whale-oil  soap,  1  lb.  to  3  or  4  gals,  water,  for  larvae. 

References. — Circ.  121,  U.  S.  Bureau  of  Entomology;  Bull. 
N.  Y.  State  Museum,  Vol.  9,  No.  46;  Bull.  143,  Conn.  Experiment 
Station;  Special  Bull.  Hatch  Experiment  Station,  (Mass.),  1899; 
Bull.  43,  la.  Experiment  Station;  Bull.  136,  N.  Y.  Experiment 
Station. 

Oyster-shell  Scale 
Lepidosaphes  ulmi  L. 

Importance. — Commonest  and  most  wide-spread  of  orchard 
scales. 

Distribution . — Probably  a  European  species;  now  cosmo¬ 
politan.  Occurs  throughout  the  United  States,  and  in  all  the 
Canadian  provinces.  Larvae  carried  on  feet  of  birds,  on  various 
insects,  and  possibly  also  by  the  wind.  Distribution  on  nursery 
stock. 

Food  Plants. — More  than  one  hundred.  Commonest  on  ap¬ 
ple,  poplar,  lilac,  willow,  elm,  maple,  and  ash.  On  most  of  the 
common  fruit  trees  and  shade  trees. 

Injuries. — Trees  stunted  and  weakened.  Incrusted  trees 
killed  by  the  scale  insect. 

Descriptions. — Male  and  female  scales.  Adult  males  and  fe¬ 
males.  Larvae.  Eggs. 

Life  History. — Winters  in  the  egg.  Eggs  white,  50  to  100  per 


9 


female.  Eggs  hatch  by  May  15  (Urbana) ;  shortly  after  the  apple 
petals  fall.  Development  of  the  scale.  Females  full  grown  by 
August  1 ;  oviposit  during  the  latter  part  of  August. 

Natural  Enemies. — Predaceous  mites.  Parasitic  Hymenop- 
tera.  Coccinellidae. 

Control. — Lime-sulphur  wash.  Resistance  of  eggs  to  sprays. 
Whale-oil  soap,  2  lbs.  to  1  gal.  water,  for  larvae.  Kerosene-soap 
emulsion,  15  percent,  for  larvae. 

References. — Girc.  121,  U.  S.  Bureau  of  Entomology;  Bull. 
N.  Y.  State  Museum,  Vol.  9,  No.  46;  Bull.  64,  Del.  Experiment  Sta¬ 
tion;  Bull.  143,  Conn.  Experiment  Station;  Bull.  Ill,  Md.  Ex¬ 
periment  Station;  Bull.  43,  la.  Experiment  Station;  Bull.  136, 
N.  Y.  Experiment  Station. 

San  Jose  Scale 
Aspidiotus  perniciosus  Gomst. 

Importance. — “A  permanent  menace  to  horticulture”  in  the 
United  States. 

Distribution. — A  native  of  China.  Introduced  into  Japan, 
Hawaii,  Chile,  Australia,  United  States,  Canada.  San  Jose  val¬ 
ley,  California,  1870;  a  pest  there  by  1873;  New  Jersey,  1886  or 
1887.  Present  distribution  in  North  America.  Distribution  on 
nursery  stock  or  cuttings;  little  danger  from  distribution  on 
fruit.  Natural  distribution  of  larvae  by  means  of  wind,  birds, 
insects,  etc.  Spread  of  larvae  on  a  tree. 

Food  Plants. — Britton  lists  72  species  as  being  commonly  in¬ 
fested,  including  all  the  common  fruit  trees,  currant,  rose,  lilac, 
poplar,  willow,  elm,  Osage  orange,  basswood,  privet;  66  species 
occasionally  infested,  as  raspberry,  blackberry,  mulberry,  grape, 
maple,  ash,  catalpa,  birch,  walnut,  spruce,  alder,  elder;  76  species 
not  infested,  as  magnolia,  tulip-tree,  butternut,  hickory,  oak,  and 
most  coniferous  trees.  Exemption  of  citrus  plants,  excepting  the 
trifoliate  orange.  Exemption  of  certain  varieties,  as  Kieffer  pear. 

Injuries. — Appearance  of  an  infested  tree.  Rapid  death  of 
affected  branches  and  of  entire  tree.  Purplish  discoloration  of 
green  fruit  and  green  bark.  Effects  of  insect  on  cambium  and 
sapwood.  Injury  to  fruit. 

Descriptions. — Scale  of  adult  female:  circular,  diameter  2 
mm.,  almost  flat,  nipple  central  and  prominent,  ring  distinct; 
color  usually  gray,  sometimes  yellowish  gray  or  blackish;  exu¬ 
viae  lemon-yellow.  Scale  of  adult  male:  oblong  oval,  twice  as 
long  as  wide,  length,  1  mm.,  nipple  between  center  and  anterior 


10 


margin;  color  gray,  buff,  or  black;  ring  distinct.  Scales  of  hi¬ 
bernating  insects:  small,  circular,  black,  volcano-like  in  form, 
with  prominent  central  nipple  surrounded  by  a  deep  ring-like 
depression.  Adult  female:  microscopical  characters.  Adult 
male.  Larva. 

Life  History  and  Habits. — Winters  in  the  “black”  stage. 
Males  issue  in  April.  Females  bear  living  young.  Earliest  larvee 
in  May.  One  to  three  generations  in  central  Illinois.  Larval 
habits:  active  12  to  48  hours;  locomotion;  influence  of  tempera¬ 
ture  on  activity.  Development  of  the  scale.  Male  and  female 
larvae  alike  until  after  the  first  molt.  The  process  of  molting. 
The  female  molts  twice;  the  male,  four  times.  Exuviae.  De¬ 
velopment  of  the  female.  Reproduction. 

Natural  Enemies. — Eight  species  of  parasites.  A  predaceous 
mite.  Predaceous  Goccinellidae.  Experiments  with  the  fungus 
Sphserostilbe  coccophila. 

Control. — Legislation  against  the  San  Jose  scale.  Nursery 
inspection.  Operations  of  the  State  Entomologist  of  Illinois. 

Fumigation  of  nursery  stock  with  HGN;  KGN  (1  oz.)  H2S04 
(1  oz.),  H20  (3  oz.),  per  100  cubic  feet.  Dipping. 

Fumigation  of  large  trees,  as  practiced  in  California;  ex¬ 
periments  in  Illinois. 

Soap  washes.  Fish-oil  soap,  2  lbs.  to  1  gal.  water. 

Danger  from  use  of  sprays  containing  kerosene  or  petro¬ 
leum. 

Lime-sulphur  wash.  Method  of  preparation:  lime,  15  lbs., 
sulphur,  15  lbs.,  water,  50  gals,  (cost  42  cents.)  Cautions  con¬ 
cerning  preparation  and  application. 

Self-boiled  lime-sulphur  wash:  preparation,  uses. 

Concentrated  lime-sulphur:  convenience,  cost. 

Chemistry  of  lime-sulphur  wash;  insecticidal  effects. 

References : — 

General:  Bull.  3,  12,  62,  U.  S.  Division  of  Entomology; 
Bull.  N.  Y.  State  Museum,  Vol.  9,  No.  46.  Food  plants:  Rep. 
State  Entomologist,  Conn.,  1902;  Bull.  62,  U.  S.  Division  of  En¬ 
tomology.  Natural  Enemies:  Bull.  62,  67,  U.  S.  Division  En¬ 
tomology;  Bull.  41,  Fla.  Exper.  Station.  Fumigation:  Bull.  57, 
131,  Md.  Exper.  Station;  Bull.  122,  Cal.  Exper.  Station;  Bull.  80, 
Ill.  Exper.  Station.  Lime-sulphur  wash:  Bull.  107,  Ill.  Exper. 
Station;  Girc.  124,  U.  S.  Bureau  Entomology;  Bull.  144,  169,  Ohio 
Exper.  Station.  Self -boiled  lime-sulphur:  Bull.  228,  273,  N.  Y. 
Exper.  Station;  Bull.  169,  Ohio  Exper.  Station;  Bull.  99,  Md.  Ex- 


11 


per.  Station;  Bull.  18,  Mo.  State  Fruit  Exper.  Station.  Concen¬ 
trated  lime  -  sulphur :  Bull.  18,  Mo.  State  Fruit  Exper.  Station. 
Chemistry  of  lime-sulphur  wash :  Bull.  101,  U.  S.  Bureau  of 
Chemistry;  Bull.  56,  Wash.  Exper.  Station;  Bull.  228,  N.  Y. 
Exper.  Station. 

Cherry  Scale,  Forbes  Scale 
Aspidiotus  forbesi  Johns. 

Economic  Importance. —  - .  Distribution. — Illinois, 

Michigan,  Ohio,  New  York,  Massachusetts,  Connecticut,  Mary¬ 
land,  Georgia,  West  Virginia,  Iowa,  Kansas,  New  Mexico.  On¬ 
tario,  Quebec,  Nova  Scotia. 

Food  Plants  and  Injuries. — Chiefly  cherry,  wild  or  culti¬ 
vated.  Apple,  pear,  plum,  quince,  currant,  peach,  hawthorn,  ash. 
Principally  on  trunk  and  branches.  Less  destructive  than  scurfy 
scale. 

Descriptions. — Scales  of  female;  of  male.  Adult  female; 
adult  male.  Larvae.  Eggs.  Comparison  with  San  Jose  scale. 

Life  History. — Winters  as  partly  grown  insect.  Two  annual 
generations.  Males  emerge  about  April  15.  Larvae  early  in  May. 
Second  generation  of  males,  July  10  to  August  1.  Larvae  during 
August  and  September. 

Natural  Enemies. — Hymenopterous  parasites.  Goccinellidae. 

Control. — Lime-sulphur  wash.  Whale-oil  soap.  Kerosene- 
soap  emulsion. 

References. — Bull.  Ill.  State  Lab.  Nat.  Hist.,  Vol.  IV.,  p.  380; 
Bull.  N.  Y.  State  Museum,  Vol.  9,  No.  46;  Bull.  43,  la.  Exper. 
Station. 

Putnam  Scale 
Aspidiotus  ancylus  Putn. 

Economic  Importance. —  - .  Distribution. — United 

States  east  of  Rocky  Mountains.  Washington.  Canada. 

Food  Plants  and  Injuries. — About  forty  plants,  chiefly  maple 
and  currant.  Apple,  pear,  plum,  peach,  cherry,  ash,  Osage 
orange,  willow,  hawthorn,  box-elder,  lilac,  etc.  Occasionally 
destructive  when  abundant. 

Descriptions. — Scales  of  male  and  of  female.  Adult  males 
and  females.  Eggs.  Larvae.  Comparison  with  San  Jose  scale. 

Life  History. — Winters  partly  grown.  One  generation.  Males 
late  in  April.  Eggs  (30  or  40  per  female)  in  late  spring  or  early 
summer.  Larvae  active  in  July. 


library 

UNIVERSITY  OF  ILLINOIS 


12 


Natural  Enemies. — Chalcididee. 

Control. — Lime-sulphur.  Whale-oil  soap.  Kerosene-soap 
emulsion. 

References. — Bull.  N.  Y.  State  Museum,  Vol.  9,  No.  46;  Bull. 
43,  la.  Exper.  Station;  Proc.  Davenport  Academy  Sciences,  Vol.  2, 
p.  346. 

CORN  INSECTS 
Corn  Root-louse 
Aphis  maidiradicis  Forbes 

Economic  Importance. — - .  Distribution. — United 

States  east  of  Rocky  Mountains,  in  almost  all  states  where  corn 
is  grown. 

Food  Plants. — Indian  corn.  Sorghum  and  broom-corn  to  a 
slight  extent.  Cotton,  strawberry,  pumpkin,  squash,  smartweed, 
foxtail  (pigeon)  grass,  crab-grass,  purslane,  dock,  mustard, 
dandelion,  plantain,  pigweed,  cocklebur,  sorrel,  and  many  other 
weeds.  Does  not  thrive  on  wheat,  oats,  rye,  cow-peas,  or  clover. 

Injuries. — Corn  plants  stunted  and  yellowish ;  may  be  killed 
in  a  dry  season.  Presence  of  ants.  Retardation  of  growth  of 
plant.  Large  numbers  of  barren  stalks  or  nubbins  on  affected 
plants.  Injury  that  is  due  to  the  removal  of  soil  from  the  roots 
by  the  ants.  Intensification  of  injury  by  drought. 

Descriptions. — Egg,  viviparous  female  (wingless  or  winged), 
oviparous  female,  male.  Species  of  ants  that  attend  the  root- 
louse. 

Life  History  and  Habits. — Winters  in  the  egg,  in  ants’  nests. 
Care  of  eggs  by  ants.  Eggs  begin  to  hatch  April  8  (Urbana). 
Transfer  of  root-lice  by  ants  to  roots  of  smartweed  or  pigeon- 
grass,  and  later  to  roots  of  corn  or  other  plants.  Number  of 
generations:  maximum,  22;  minimum,  11.  Birth  to  maturity, 
8.1  days.  Bearing  period,  10.6  days.  Length  of  life  of  viviparous 
female,  20.1  days.  Number  of  young  per  day,  per  female:  aver¬ 
age,  4;  maximum,  11.  Total  number  of  young  per  female:  av¬ 
erage,  44;  maximum,  96.  Oviposition  in  October  and  November. 
Eight  generations  present  at  one  time  in  autumn.  Relations  be¬ 
tween  ants  and  aphids. 

Natural  Checks. — Freedom  from  predaceous  or  parasitic  en¬ 
emies.  Effects  of  heavy  rains. 

Control. — Rotation.  Spring  plowing.  Experiments  on  ad¬ 
ditional  cultivation.  Use  of  repellents  on  seed-corn.  Advan¬ 
tages  and  disadvantages  of  oil  of  lemon.  Danger  from  kerosene. 
Three  ounces  of  3-percent  carbolic  acid  in  water  to  each  gallon 


13 


of  seed-corn.  Three  ounces  of  4-percent  formalin  per  gallon  of 
seed. 

References. — 17th  and  18th  Reports,  State  Ent.,  Illinois;  Bull. 
104,  130,  131,  178,  Ill.  Exper.  Station;  Bull.  12,  Pt.  8,  tech,  ser.,  U. 
S.  Bureau  of  Entomology;  Bull.  85,  Pt.  6,  U.  S.  Bureau  of  Ento¬ 
mology;  10th  Report,  Ill.  Farmers’  Institute,  1905. 

Northern  Corn  Root-worm 
Diabrotica  longicornis  Say 

Economic  Importance. —  - .  Distribution. — Injuries  in 

Missouri,  Kansas,  Iowa,  Nebraska,  Illinois,  Indiana,  Ohio.  Oc¬ 
curs  also  in  Kentucky,  New  York,  Arizona,  New  Mexico,  Canada, 
and  Central  America. 

Food  Plants. — Chiefly  Indian  corn;  also  sorghum  and  broom- 
corn. 

Injuries. — Corn  plant  retarded  in  all  stages  of  its  growth  and 
development.  Barren  stalks;  nubbins;  soft  ears;  lodging  of  plant. 
Injury  intensified  by  drought.  Roots  die  from  tip  toward  base; 
loss  of  many  rootlets;  bark  of  root  loosened  by  burrows  of 
larvae.  Beetles  feed  on  silk  and  pollen,  without  causing  serious 
injury;  injure  flowers  of  clover  and  rinds  of  cucurbits. 

Descriptions. — Egg,  larva,  pupa,  imago.  Distinguish  from 
wireworms,  dipterous  larvae,  etc. 

Life  History. — One  generation.  Winters  in  the  egg,  in  old 
corn-fields.  Eggs  hatch  May  15  to  July  15  in  latitude  of  central 
Illinois.  Larvae  occur  until  last  part  of  August.  Pupation  in  the 
soil,  among  the  corn  roots.  Beetles  emerge  in  July  and  August. 
Feeding  habits  of  beetles.  Oviposition. 

Control. — Rotation;  follow  corn  with  oats  or  wheat,  for  ex¬ 
ample.  Two-year  period  in  corn. 

References. — 12th  and  18th  Reports,  State  Ent.,  Illinois;  Bull. 
44,  60,  Ill.  Exper.  Station;  Bull.  51,  Ohio  Exper.  Station;  Circ.  59, 
U.  S.  Bureau  Entomology;  10th  Report,  Ill.  Farmers’  Institute, 
1905. 

White-grubs 

Lachnosterna  and  Cyclocephala 

Importance. — Among  the  worst  enemies  of  cultivated  plants. 
Lachnosterna, — some  forty  species  in  Illinois,  eight  of  them  in¬ 
jurious  to  corn;  Cyclocephala, — one  species,  on  corn  and  grass. 
Melolontha  in  Europe. 

Food  Plants  and  Injuries. — White-grubs  natives  of  prairie 
sod.  Injury  to  pastures  and  lawns,  especially  in  times  of  drought. 


14 


Injury  to  corn,  wheat,  barley,  etc.,  particularly  on  newly  broken 
sod  land.  All  cereals  affected;  potatoes,  sugar-beets,  beans, 
strawberries.  Injury  in  young  nurseries.  Glover  practically  im¬ 
mune.  Injury  by  beetles  to  foliage  of  fruit,  shade,  and  forest 
trees.  Effects  on  corn;  plants  dwarfed  or  killed;  leaves  yellow¬ 
ish;  effects  are  like  those  of  drought,  and  are  intensified  by  lat¬ 
ter;  leaning  and  lodging  of  plants;  barren  stalks;  nubbins;  roots 
eaten  away,  leaving  short  stubs.  Bare  spots  in  corn  field  in 
autumn,  with  grubs  in  the  hills.  Corn  injured  for  two  years 
following  sod. 

Descriptions. — Eggs,  larvae  (“white-grubs,”  “grub-worms”), 
pupae,  beetles  (“May-beetles,”  “June-bugs”).  Differences  between 
Lachnosterna  and  Cyclocephala. 

Life  History  and  Habits. — Life  cycle,  between  two  and  three 
years.  Studies  on  the  life  history  in  Illinois  by  Forbes.  Ovi- 
position  in  June  and  July;  egg  period,  10  to  18  days.  Feeding 
habits  of  grubs;  descent  to  escape  frost.  Pupation  in  summer 
(pupal  period  abont  three  weeks).  Beetles  emerge  from  pupae  in 
August  or  September,  but  remain  in  the  soil  over  winter.  Winter 
passed  as  beetle  or  larva.  Habits  of  beetles.  Some  of  the  beetles  of 
June,  1914,  are  from  eggs  laid  about  June,  1911.  Periodicity 
of  adults  of  cockchafer  in  Europe. 

Vertebrate  Enemies. — Toads  and  frogs  eat  the  beetles.  Moles 
and  ground-squirrels  (grubs) ;  skunks  (grubs  and  beetles) ;  rac¬ 
coon  (beetles).  Pigs  (see  Control).  Grubs  and  beetles  eaten  by 
robin,  blackbirds,  English  sparrow,  crow,  hawks,  owls;  grubs 
by  blue  jays,  yellowhammers ;  beetles  by  catbird,  thrushes,  blue¬ 
bird.  Chickens,  ducks,  and  turkeys  destroy  both  grubs  and 
beetles;  poultry,  in  freshly  plowed  fields.  Birds  that  destroy 
grubs  in  lawns. 

Insect  Enemies. — Pelecinus,  Tiphia,  Ophion,  Sparnopolius, 
Pyrgota,  Tachinidee,  Garabidee,  ants,  mites. 

Fungi. — Cordyceps,  Sporotrichum,  Isaria;  experiments  in 
Illinois. 

Control. — Break  sod  the  year  before  it  is  to  be  put  into  corn. 
Pasture  hogs  on  meadows  or  pastures  before  plowing  for  corn. 
Use  of  poultry,  following  the  plow.  Hand  picking  in  gardens.  Cul¬ 
tivation  and  fertilization  to  strengthen  plants.  Rotation;  freedom 
of  clover  from  attack.  Experiment  at  Ludlow  in  clearing  infested 
field  of  grubs.  Control  of  beetles :  by  use  of  arsenicals ;  practice 
of  jarring  in  Europe;  light  traps  (mostly  males  attracted) ;  pigs 
in  orchards  and  woodlands. 


15 


References. — 17th,  18th,  and  20th  Reports,  State  Ent.  Ill.; 
10th  Report,  Ill.  Farmers’  Institute,  1905;  Bull.  116,  Ill.  Exper. 
Station;  Bull.  19,  U.  S.  Division  Entomology. 

Wireworms 

Melanotus  and  other  Genera 

Importance. —  Eight  species  injurious  to  corn  in  Illinois. 

Food  Plants  and  Injuries. — Corn,  wheat,  rye,  barley,  oats, 
potatoes,  turnips,  cabbages,  carrots,  beets,  onions,  lettuce,  straw¬ 
berry,  and  many  garden  plants.  Grass  the  main  food  of  injuri¬ 
ous  species.  Injury  to  corn  following  sod.  Failure  of  seed-corn 
to  start;  sudden  withering  of  young  plants.  Wireworms  eat 
or  bore  into  seeds,  roots,  or  bases  of  stems  of  corn. 

Descriptions. —  Larvae,  pupae,  adults. 

Life  Histories  and  Habits. — Melanotus  communis :  Larval 
period  not  less  than  three  years;  pupation  in  July  in  an  earthen 
cell;  pupal  period  one  month;  beetles  common  in  September, 
and  winter  under  bark  of  trees  or  in  the  ground  or  elsewhere. 
Habits  of  the  beetles,  known  as  “click-beetles”  or  “skip-jacks”; 
beetles  abundant  in  April,  May,  and  June. 

Melanotus  fissilis :  Abundant  in  Middle  and  Southern 
States.  Life  history  similar  to  that  of  M.  communis. 

Melanotus  cribulosus :  The  commonest  wireworm  in  corn 
fields  in  Illinois.  Does  considerable  damage  to  corn  on  sod  land 
the  first  year,  and  more  damage  the  second  year.  Larvae  common 
in  June  and  July.  Larval  period  about  two  years.  Pupates  in 
August,  in  the  ground.  Adults  emerge  from  pupa  in  September, 
but  may  remain  in  the  ground  over  winter. 

Agriotes  mancus:  Very  injurious  to  small  grains  and  to 
corn.  In  corn  following  sod.  Larval  period  probably  three  years 
at  least.  Pupates  in  July,  in  the  ground.  Beetles  emerge  from 
pupae  by  September,  but  remain  in  the  ground  over  winter. 

Drasterius  elegans :  Abundant.  Especially  injurious  to 
young  wheat  and  to  corn.  Larval  period  about  two  years. 
Beetles  hibernate  under  leaves,  boards,  rubbish,  etc.,  and  are 
common  in  May,  June,  and  July. 

Natural  Enemies  of  Wireworms. — Grow  (worms  and 
beetles) ;  and  the  robin,  blackbirds,  and  thrushes  destroy  large 
numbers  of  wireworms. 

Control. — Experiments  with  repellents  used  on  seed-corn. 
Late  fall-plowing.  Rotation.  Late  replanting,  between  the  old 
rows.  Fertilizers.  Poisons,  for  use  in  gardens. 


16 


References. — 18th  Report,  State  Ent.  Ill.;  Bull.  33,  107, 
Cornell  Exper.  Station;  4th  Report,  Cornell  Exper.  Station;  Bull. 
46,  Ohio  Exper.  Station;  Fitch’s  11th  Report,  Insects  of  New  York; 
Bull.  44,  Ill.  Exper.  Station;  Bull.  43,  U.  S.  Division  of  Ento¬ 
mology;  10th  Report,  Ill.  Farmers’  Institute,  1905. 

Corn  Cutworms 

Hadena,  Agrotis,  Peridroma ,  Noctua,  Feltia,  Nephelodes 

Economic  Importance. —  - .  Food  Plants. — Grasses, 

clover,  corn,  small  grains,  garden  vegetables. 

Injuries. — Most  destructive  to  crops  following  grass  or 
clover.  Cut  off  plants  near  the  ground.  Eat  leaves  and  stalks. 
Replanting  often  necessary. 

Descriptions. — General  characteristics  of  cutworms  and  their 
moths. 

Life  Histories  and  Habits. — Most  species  winter  as  partly 
grown  caterpillars,  become  full  grown  late  in  June  or  early  in 
July,  and  pupate  in  the  soil.  One  to  three  annual  generations, 
according  to  the  species.  Cutworms  hide  during  the  daytime; 
often  buried  near  plants  they  have  attacked.  Moths  attracted 
by  lights. 

Control. — Plow  grass-lands  in  midsummer  or  early  fall. 
Pasture  pigs  on  grass  or  clover  lands.  Replant  as  late  as  pos¬ 
sible  and  between  the  old  rows.  Poisons:  Paris  green  1  lb.,  bran 
30  lbs. ;  freshly  cut  clover,  sprayed  with  Paris  green,  1  lb.  to  50 
gals,  water. 

References. — 23d  Report,  State  Ent.,  Illinois;  10th  Report, 
Ill.  Farmers’  Institute,  1905. 

Army-worm 

Heliophila  unipuncta  Haw. 

Economic  Importance. — Irregularity  of  outbreaks.  Insects 
mistaken  for  the  army- worm. 

Distribution. — Practically  cosmopolitan.  Occurs  throughout 
the  United  States  and  in  parts  of  Canada.  A  pest  in  North 
America  only. 

Food  Plants. — Grasses,  especially  timothy,  wheat,  oats,  corn, 
rye,  barley;  also  sorghum,  millet,  blue-grass,  Hungarian  grass, 
crab-grass.  Some  damage  to  flax.  Caterpillars  eat  onions,  peas, 
beans,  and  other  garden  crops ;  leaves  and  green  fruits  of  straw¬ 
berry.  Clover  rarely  if  ever  eaten;  alfalfa  very  rarely.  Cut¬ 
worms  accompanying  army-worms.  Moths  feed  on  nectar  of 


17 


flowers,  as  clover,  apple,  honeysuckle;  on  juices  of  fallen 
peaches;  on  banana  skins.  Attracted  to  molasses  placed  on 
trees. 

Injuries. — Army-worms  develop  in  neglected  parts  of 
meadows,  and  pastures.  Feed  by  night  mostly,  avoiding  bright 
sunlight.  Eat  all  but  the  tougher  parts  of  plants.  Cause  bare 
patches  in  meadows.  Forced  by  lack  of  food  to  migrate  in 
“armies”.  May  reduce  a  field  of  corn  to  bare  stalks,  destroy  all 
the  green  oats  or  wheat,  cut  off  heads  of  timothy  or  small  grains. 
One  hundred  acres  of  blue-grass  destroyed  in  five  days. 

Descriptions. — Eggs;  appearance  of  egg  masses.  Distin¬ 
guishing  characters  of  the  caterpillar,  pupa,  and  moth. 

Life  History  and  Habits. — Three  annual  generations  in  this 
latitude.  First  generation  destructive  in  southern  Illinois  (early 
in  June) ;  second  in  northern  Illinois  (July) ;  third,  rarely  in¬ 
jurious.  With  rare  exceptions,  only  one  of  these  generations 
is  destructive  in  any  one  place  the  same  year;  reasons  for  this. 

Passes  the  winter  as  a  partly  grown  caterpillar  or  as  a  moth. 
Moths  flying  late  in  autumn  and  early  in  spring.  Attracted  to 
lights  and  to  “sugar”.  Overlapping  of  generations.  Larvae  that 
have  hibernated  become  active  in  late  March  or  early  April 
(Illinois) ;  larvae  from  eggs  of  wintered  moths  appear  in  May; 
first  brood  thus  a  composite  one;  effects  of  this  on  later  broods. 
Moths  occur  throughout  the  season.  Second  generation  of  larvae 
active  in  July;  third,  in  September.  Egg  period  about  nine  days; 
larval,  three  to  four  weeks;  pupal,  two  weeks  in  summer,  three 
to  four  weeks  in  spring. 

Armies  may  number  millions  of  individuals,  and  will  travel 
and  feed  in  bright  weather,  unless  sunlight  is  too  strong.  Worms 
may  be  three  deep  in  one  of  these  armies,  which  may  be  a  half 
a  mile  or  more  in  width.  Travel  three  feet  in  one  minute  some¬ 
times. 

Pupation  occurs  in  the  soil,  an  inch  or  two  below  the  sur¬ 
face,  or  under  stones  or  rubbish,  etc. 

Swarming  and  migration  of  the  moths. 

Hatural  Enemies.-— Chickens,  turkeys,  ducks,  geese.  All  the 
insectivorous  birds,  particularly  the  robin,  blackbirds,  meadow¬ 
lark,  kingbird,  catbird,  English  sparrow,  and  quail.  Shrews, 
skunks.  Toads,  frogs.  Carabidae,  Gicindelidae.  Tachinidae. 
Braconidae.  Ghalcididae.  Ichneumonidae.  Sarcophagidae.  Fun¬ 
gous  parasite  ( Empusa ). 

Control. — Watch  grass-lands  in  spring,  for  local  injury;  use 


18 


of  a  furrow  to  surround  a  colony ;  killing  with  arsenicals  or  by 
burning.  Protection  from  an  army  by  means  of  a  furrow,  with 
the  steep  side  toward  the  field  to  be  protected;  post-holes  a  rod 
apart;  kill  with  kerosene,  or  by  burning,  or  with  earth  pound  d 
down.  Use  of  hogs,  poultry,  and  sheep.  Burn  over  fields  in 
winter  or  early  spring.  Method  of  poisoning:  use  Paris  green, 
1  lb.;  bran,  16  lbs.;  with  water  and  a  little  salt, — to  make  a  bran 
mash  that  crumbles  readily.  Experiments  in  southern  Illinois 
with  this  method. 

References. — 23d  Report,  State  Ent.,  Ill.;  10th  Report,  Ill. 
Farmers’  Institute,  1905;  Bull.  95,  Ill.  Exper.  Station;  Bull.  96, 
Ohio  Exper.  Station;  Bull.  104,  133,  N.  Y.  Exper.  Station;  Bull. 
157,  Ky.  Exper.  Station. 

Corn  Bill-bugs 
Sphenophorus 

Importance. — Local  injury  in  Illinois. 

Distribution. — General  in  the  United  States  and  Canada. 

Food  Plants. — Larvae  feed  on  roots  of  upland  grasses,  swamp- 
grasses,  or  sedges;  beetles  feed  on  same  plants  as  their  larvae, 
and  injure  corn  also. 

Injury. — Under  three  conditions:  (1)  in  swamp  land  broken 
up  from  grass  in  spring  and  planted  to  corn  the  same  year;  (2) 
in  such  land  poorly  cultivated  where  the  swamp  grasses  are  not 
kept  down;  (3)  in  old  timothy  sod,  broken  in  spring  and  put 
into  corn  at  once.  S.  parvulus  develops  in  timothy  bulbs,  the 
beetle  going  to  blue-grass,  corn,  or  wheat  to  feed,  but  doing 
little  damage  ordinarily.  S.  ochreus  bores  into  the  stalks  or  buds 
of  corn,  sometimes  doing  great  damage.  Characteristic  leaf- 
punctures  of  the  bill-bugs. 

Descriptions. —  Distinguishing  characters  of  the  more  im¬ 
portant  bill-bugs.  Structure  and  use  of  the  beak. 

Life  Histories. — Winter  as  beetles  on  the  ground  under  rub¬ 
bish,  or  in  other  sheltered  situations,  usually  in  fields  in  which 
they  have  developed.  Apparently  single-brooded.  Injure  corn 
before  the  middle  of  July.  Eggs  laid  in  May  and  June  in  roots 
or  stems.  Larvae  occur  throughout  summer.  Beetles  emerge  in 
late  summer  and  in  fall. 

Control. — Replant,  as  late  as  possible.  Early  fall-plowing. 

References. — Bull.  79,  Ill.  Experiment  Station;  22d  and  23d 
Reports,  State  Ent.,  Ill.;  10th  Report,  Illinois  Farmers’  Institute, 
1905. 


19 


Corn  Ear-worm 
Heliothis  obsoleta  Fab. 

Economic  Importance. — Damage  in  Illinois.  In  the  South, 
known  as  the  cotton  boll-worm,  bud-worm,  or  tassel-worm. 

Distribution. — Cosmopolitan. 

Food  Plants. — Some  eighty  species.  Injurious  in  truck 
gardens  to  potatoes,  beans,  peas,  cucurbits,  etc.  Injury  to  orna¬ 
mental  plants. 

Injuries. — Worst  injury  to  corn,  cotton,  tomato,  and  tobacco. 
Sweet  corn  subject  to  more  injury  than  field  corn,  as  it  is  planted 
earlier.  Characteristic  injury  to  ears  of  corn. 

Descriptions. — Characters  of  eggs,  larvae,  pupae,  and  adults. 

Life  History  and  Habits. — Three  generations  in  Illinois. 
Winters  as  a  pupa  in  the  soil,  within  six  inches  of  the  surface. 
Moths  emerge  in  April  or  May,  and  lay  eggs  on  tomatoes,  peas, 
corn,  etc.  Second  generation  of  caterpillars  feeds  on  tassel,  silk, 
and  soft  ears  of  corn.  Cannibalistic  habit.  Third  generation  of 
larvae  in  autumn  on  hard  corn.  Pupates  in  September  and 
October. 

Natural  Enemies. — Tachinidae.  Kingbird,  catbird. 

Control. — Plowing  after  the  corn  is  cut,  to  destroy  the  pupae. 
Corn  as  a  trap  crop,  in  the  South. 

References. — 23d  Report,  State  Ent.,  Ill.;  10th  Report,  Illinois 
Farmers’  Institute,  1905;  Farmers’  Bulletins  47,  191,  212,  U.  S. 
Department  of  Agriculture;  Bull.  24,  50,  U.  S.  Bureau  Ento¬ 
mology. 

Chinch-bug 
Blissus  leucopterus  Say 

Economic  Importance. — The  chinch-bug  and  the  Hessian 
fly  have  done  more  damage  than  any  other  insects  in  the  United 
States.  Injury  to  corn,  wheat,  and  oats  in  Illinois  in  1887  by 
chinch-bug  estimated  at  $11,840,000;  in  1871,  in  seven  states 
(Illinois,  Indiana,  Wisconsin,  Iowa,  Missouri,  Kansas,  Nebraska), 
$30,000,000.  In  1887,  its  damage  in  these  states,  with  that  in 
Ohio,  Kentucky,  and  Minnesota,  aggregated  $60,000,000. 

Distribution. — Probably  came  from  Central  America.  Guate¬ 
mala,  Panama,  Cuba,  Mexico,  New  Mexico,  California.  General 
distribution :  Texas  north  to  Manitoba  and  east  to  Atlantic  Ocean. 
Florida  to  Cape  Breton.  Paths  of  distribution. 

Food  Plants. — Originally  native  grasses.  Injurious  chiefly 
to  wheat,  barley,  rye,  and  corn.  Attacks  Hungarian  grass  and 


20 


millet;  timothy,  in  absence  of  other  food.  Oats,  seldom.  Grab- 
grass,  pigeon-grass,  etc.  Sorghum,  broom-corn. 

Injuries. — Saps  and  kills  plants.  In  spring  affects  wheat  or 
oats,  migrating  at  harvest-time  to  corn.  Sometimes  affects  young 
corn  instead  of  small  grains.  Successive  hot  dry  summers  in¬ 
dicate  the  approach  of  a  chinch-bug  period.  Moist  weather  un¬ 
favorable  to  development  of  chinch-bug;  reasons  for  this. 

Descriptions. — Eggs:  form,  color,  size,  number,  deposition. 
Characters  of  the  chinch-bug  in  the  five  stages  of  its  development. 
Means  of  distinguishing  the  chinch-bug  from  other  bugs  mis¬ 
taken  for  it.  Short-winged  race  of  the  chinch-bug. 

Life  History  and  Habits. — Hibernates  as  adult,  among  roots 
of  grasses,  under  dead  leaves,  boards,  rail  fences,  rubbish,  under 
bark,  in  corn  shocks,  etc.  Bugs  issue  from  winter  quarters  in 
April,  fly  about,  and  infest  wheat  mostly,  though  bugs  issuing 
later  (May)  sometimes  lay  eggs  in  oats  or  young  corn.  Egg 
period  ten  days  or  three  weeks.  From  hatching  to  adult  stage, 
six  weeks.  As  the  small  grains  ripen  and  harden,  the  bugs  leave 
the  grain  fields  and  invade  corn  fields.  At  this  time  the  bugs 
migrate  on  foot,  though  many  of  them  are  capable  of  flying. 
Cast  skins  often  mistaken  for  dead  bugs.  Corn  often  black  with 
the  bugs.  Outer  rows  attacked  first.  Eggs,  for  second  genera¬ 
tion  laid  on  corn  or  on  wild  grasses.  Two  generations  a  year, 
with  a  partial  third  generation  in  Kansas  and  possibly  southern 
Illinois  also.  In  autumn  the  bugs  crawl  or  fly  to  shelter  for  the 
winter. 

Natural  Enemies. — Fungous  and  bacterial  diseases.  Experi¬ 
ments  with  Sporotrichum.  Predaceous  insects:  Triphleps ,  Agon - 
oderus,  Chrysopa,  Goccinellidae,  ants.  Bird  enemies:  quail, 
prairie  chicken,  catbird,  meadow-lark,  wren,  brown  thrush,  red¬ 
winged  blackbird.  Birds  eat  comparatively  few,  however.  Habits 
and  importance  of  Eumicrosoma  benefica. 

Control. — Difficulty  of  protecting  wheat  in  spring  from  the 
chinch-bug.  Destruction  of  bugs  in  spring  by  burning  over 
grass  lands.  Glean  farming  to  lessen  numbers  of  bugs.  Use  of 
gasoline  torch.  Method  of  making  the  dusty  furrow;  disadvan¬ 
tages.  The  Illinois  method:  Repellent  barriers,  trap-holes,  and 
a  spray  when  necessary.  Preparation  of  the  ground  for  the  re¬ 
pellent;  post-holes,  20  feet  apart,  18  inches  or  more  in  depth. 
Comparison  of  repellents  used:  gas-tar;  road  oil  No.  7;  crude 
creosote;  crude  carbolic  acid.  Maintenance  of  the  barrier.  Kill¬ 
ing  bugs  in  the  post-holes.  Cost  of  method.  Practicability  of 


21 


killing  bugs  by  spraying  in  a  few  outer  rows  of  corn  at  harvest¬ 
time,  and  in  young  corn  in  spring.  Use  of  “Black  Leaf  40”,  % 
ounce  with  1  ounce  soap  solution  to  a  gallon  of  water.  Three 
ounces  soap  to  1  gallon  water.  Cautions.  Kind  of  sprayer  to 
use. 

Necessity  of  community  cooperation  against  the  chinch- 
bug.  Mode  of  organization.  Campaigns  conducted  by  the  State 
Entomologist  of  Illinois. 

References. — Circulars  by  State  Ent.,  Ill.;  16th,  17th,  19th, 
20th,  and  23d  Reports,  State  Ent.,  Ill. ;  Bull.  69,  77,  106,  Ohio  Ex- 
per.  Station;  Bull.  51,  Mo.  Exper.  Station;  Bull.  15,  18,  U.  S.  Divi¬ 
sion  of  Entomology;  Farmers’  Bull.  132,  U.  S.  Dept.  Agriculture. 

WHEAT  INSECTS 
Hessian  Fly 

Mayetiola  ( Cecidomyia )  destructor  Say 

Economic  Importance. — Ranks  with  the  chinch-bug  in  de¬ 
structiveness.  Destroys  annually  in  the  United  States  at  least 
10  percent  of  the  wheat  crop.  Injury  in  Illinois  often  amounts 
to  several  millions  of  dollars;  in  1910,  to  $600,000  in  one  county. 

Distribution. — Europe,  Western  Asia,  North  Africa,  New 
Zealand.  Now  occurs  practically  throughout  the  wheat  belt  of 
the  United  States  and  Canada.  Introduction  into  this  country, 
possibly  in  1776.  First  attracted  attention  in  Long  Island  in 
1779;  origin  of  the  common  name.  Slowly  distributed  by  flight 
and  by  the  wind.  Tends  to  oviposit  in  the  nearest  fields.  Trans¬ 
portation  in  straw  occasionally. 

Food  Plants. — Confined  to  wheat,  barley,  and  rye.  No  good 
evidence  as  yet  that  it  develops  on  any  other  plants.  No  varieties 
of  wheat  are  “fly-proof”,  though  some  resist  the  injury  better 
than  others,  by  having  stiffer  stems  or  by  tillering  more  freely. 

Injuries. — Young  infested  plants  have  “bunchy”  or  erect 
leaves,  no  internodes;  leaves  broader  and  darker  green  than 
normal,  often  bluish  green;  easily  killed  by  frost;  tillers  show 
the  same  effects.  Plants  attacked  early  are  often  killed;  plants 
attacked  later,  after  tillers  are  formed,  may  develop  some  un¬ 
affected  stalks.  Infested  plants  turn  yellow  and  then  brown. 
In  summer  the  straw  breaks  at  the  joints  where  the  larvae  have 
been  working;  or,  sometimes,  at  the  surface  of  the  ground. 
Frequently  less  grain  ripens  than  was  sown.  In  young  plants, 


22 


larvae  at  or  below  the  surface  of  the  ground  cause  a  swelling 
of  the  base  of  leaf  and  culm. 

Descriptions . — Egg,  larva:  three  stages;  function  of  the 
“breast-bone”.  Puparium,  or  “flaxseed”.  Pupa.  Characters  of 
adults. 

Life  History  and  Habits. — Winters  in  the  flaxseed  stage,  as 
a  rule.  Two  principal  broods  (spring  and  fall)  and  in  some 
years  four.  Flies  emerge  from  late  May  to  late  June  (southern 
Illinois) ;  a  large  percentage  remain  in  the  stubble  as  flaxseeds 
at  harvest.  Influence  of  moisture  on  development.  Eggs  laid 
in  grooves  on  upper  surface  of  leaf;  egg  period,  four  days  to 
two  weeks.  Larvae  go  down  under  sheath  of  leaf  and  fix  them¬ 
selves  on  the  stem.  In  spring,  eggs  laid  mostly  near  the  first 
joint.  Larvae  often  erroneously  called  the  “eggs”  of  the  fly. 
Flies  that  emerge  from  the  stubble  lay  their  eggs  on  volunteer 
wheat.  Flies  of  fall  generation  lay  eggs  on  young  crop  of  wheat 
in  September  and  early  October.  Will  oviposit  even  in  frosty 
weather.  Adults  said  to  live  but  three  days  at  most,  apparently 
without  feeding. 

Natural  Enemies. — Influence  of  parasites  on  the  Hessian 
fly.  Ghalcididae.  Proctotrypidae. 

Control. — 1.  Sow  on  new  ground,  not  in  wheat  the  preceding 
year.  Do  not  sow  wheat  on  infested  stubble. 

2.  Prepare  a  good  seed-bed,  finely  pulverized  and  compact. 

3.  Use  good  seed;  test  it. 

4.  Select  varieties,  other  things  equal,  with  a  hard  straw 
and  which  tiller  freely. 

5.  Burn  stubble  after  harvest;  method  of  doing  this;  often 
impracticable  where  clover  or  timothy  are  with  wheat.  Plow 
stubble  under,  if  possible,  after  harvest,  and  roll. 

6.  Burn  chaff,  screenings,  and  other  waste  from  infested 
fields. 

7.  Destroy  volunteer  wheat,  by  plowing,  disking,  or  oth  r- 
wise,  before  larvae  have  matured.  Plow  and  roll  when  three 
or  four  inches  high.  Use  of  trap  strips  of  wheat.  Rotation. 

9.  Late  sowing:  In  an  average  year,  northern  Illinois,  Sep¬ 
tember  20;  central  Illinois,  September  30;  southern  Illinois,  Octo¬ 
ber  10.  Sowing  “after  the  first  hard  frost”.  Importance  of  co¬ 
operation  in  late  sowing  in  a  community.  One  who  sows  wheat 
too  early  raises  Hessian  flies  for  his  neighbors. 

References. — Circ.  146,  Ill.  Experiment  Station;  14th,  15th, 
and  17th  Reports,  State  Ent.,  Ill.;  Circ.  70,  U.  S.  Bureau  of  Ento- 


23 


mology;  Bull.  16,  U.  S.  Division  of  Entomology;  Bull.  107,  119, 
136,  177,  Ohio  Exper.  Station;  Bull.  103,  111,  Ky.  Exper.  Station; 
Bull.  62,  Mo.  Exper.  Station;  Bull.  194,  Cornell  Exper.  Station. 

CLOVER-SEED  INSECTS 

The  problem  of  raising  a  good  crop  of  red-clover  seed  is 
primarily  entomological.  The  methods  about  to  be  given  have 
enabled  many  Illinois  farmers  during  the  last  five  years  to  double 
their  yield  of  clover  seed. 

High  prices  of  clover  seed  are  due  primarily  to  the  fact  that 
comparatively  few  farmers  know  how  to  raise  seed  profitably. 
Even  successful  seed-growers  who  know  the  right  methods 
seldom  understand  precisely  how  these  methods  operate  to  pro¬ 
duce  good  results. 

Average  yield  of  seed  in  the  black  soil  of  the  corn  belt,  1.5  bu. 
per  acre;  largest  yields,  9  bu.  (Indiana),  10  bu.  (Idaho).  Red 
clover  practically  a  biennial  on  prairie  soil,  though  many  plants 
will  live  for  more  than  two  years;  a  perennial  in  the  north¬ 
western  states  and  on  the  Pacific  slope. 

Pollination. — Red  clover  can  not  pollenize  itself.  Gross- 
pollination  is  performed  chiefly  by  bumblebees.  Examples  of 
the  many  experiments  that  prove  this.  Brief  account  of  the  life 
history  of  bumblebees.  Red  clover  does  not  set  much  seed  in 
the  June  crop,  as  a  rule,  because  there  are  not  enough  bumble¬ 
bees  to  pollenize  the  flowers,  the  only  winged  bumblebees  at 
that  time  being  the  comparatively  few  queens  that  have  sur¬ 
vived  the  winter.  In  midsummer,  however,  there  are  ordinarily 
enough  bumblebees  to  pollenize  the  second  crop.  Average  num¬ 
ber  of  these  bees  in  a  clover  field  in  bloom;  rate  at  which  the 
flowers  are  pollenized.  Experiments  made  by  us  in  raising 
bumblebees  artificially.  Boys  on  the  farm  should  be  instructed 
not  to  kill  bumblebees  wantonly. 

Every  year  there  is  some  seed  in  June;  now  and  then  a 
bushel  or  a  bushel  and  a  half  to  the  acre  in  this  or  that  locality. 
This  unexpected  yield  of  seed  in  June  is  due,  so  far  as  has  been 
ascertained,  to  pollination  by  honey-bees  of  the  long-tongued 
variety  (Italian).  Circumstances  under  which  honey-bees  can 
pollenize  red  clover. 

A  negligible  amount  of  pollination  is  probably  performed 
accidentally  by  minute  insects  that  commonly  occur  in  clover 
heads,  such  as  Euthrips  and  Triphleps. 

The  structure  of  the  blossom  of  red  clover.  Mechanism  of 


24 


cross-pollination.  Reasons  for  the  failure  of  artificial  pollination 
by  the  brush-machine. 

Rules  for  Raising  Clover  Seed. — 1.  Pasture  to  sheep  in 
spring,  after  the  clover  has  made  a  good  start,  turning  them  off 
in  early  June.  A  good  method  where  many  sheep  are  raised, 
though  the  next  method  is  better  adapted  to  the  conditions  in 
Illinois. 

2.  Clip  the  clover  twice:  in  the  middle  of  May  and  the  last 
of  June,  in  an  average  season  in  central  or  northern  Illinois. 
In  a  wet  season,  when  the  clover  grows  rapidly,  three  clippings 
may  be  necessary.  Clip  before  the  growth  is  so  heavy  that  the 
clippings  will  smother  the  new  growth,  or  use  next  method. 

3.  Gut  the  June  hay  crop  early,  when  one-third  or  one-half 
of  the  field  is  fresh  in  bloom.  This  early-cut  clover  will  cure 
perfectly,  notwithstanding  statements  to  the  contrary.  Glover 
cut  in  July  is  woody  and  makes  poor  fodder,  and  the  following 
new  growth  can  not  be  expected  to  yield  much  seed.  It  is  pos¬ 
sible  to  get  a  good  hay  crop  and  a  good  seed  crop  in  the  same 
year,  if  one  wishes  to  do  so.  The  plowing  under  of  clover  from 
time  to  time,  for  the  sake  of  the  nitrogen,  is  highly  important, 
but  does  not  form  a  part  of  the  present  subject. 

4.  Gut  (or  pasture)  red  clover  in  the  latter  part  of  its  first 
year’s  growth  to  destroy  the  heads  that  flower  prematurely,  or 
to  prevent  their  formation.  In  some  moist  seasons  a  paying  crop 
of  clover  hay  may  be  obtained  in  the  first  year.  Gut  the  clover 
a  few  weeks  after  the  oats  are  harvested,  and  early  enough  to 
allow  a  good  growth  before  frost  comes. 

5.  Destroy  volunteer  clover.  This  may  conveniently  be  done 
when  the  hay  crop  or  seed  crop  is  cut,  cutting  at  the  same  time 
the  clover  that  grows  wild  on  the  borders  of  the  field  or  the  sides 
of  the  road. 

The  reasons  for  these  methods  will  appear  after  the  habits 
of  the  seed-insects  have  been  discussed.  These  seed  pests  are 
of  three  species.  They  are  abundant  in  Illinois  in  every  field 
where  clover  is  grown  (unless  they  have  been  guarded  against), 
and  often  destroy  fifty  to  seventy-five  percent  of  the  possible 
yield  of  seed.  The  two  worst  pests  are  so  small  that  they  escape 
notice,  and  the  third — the  seed-caterpillar — though  compara¬ 
tively  large,  is  not  often  seen  on  account  of  its  habits. 

Glover  Seed-midge 
Dasyneura  leguminicola  Lintn. 

Flies  of  first  generation  most  abundant  May  25,  in  central 


25 


Illinois,  in  an  average  season;  in  other  words,  at  the  time  when 
the  green  clover-heads  are  most  numerous.  How  to  find  and 
recognize  the  midges;  oviposition;  egg  period.  Habits  of  the 
larvae.  Appearance  of  infested  heads.  A  simple  means  of  de¬ 
termining  the  amount  of  infestation  in  a  clover  field.  Larvae 
become  full  grown  and  begin  to  leave  the  clover  heads  by  June 
20 — an  important  date,  from  the  standpoint  of  control.  Pupate 
in  the  soil.  Second  generation  of  adults  on  the  wing  in  early 
August,  to  lay  eggs  on  the  seed  crop.  Third,  and  most  abundant 
generation,  flying  in  September,  and  laying  eggs  in  first-year 
clover. 

Control. — If  the  clover  has  been  pastured  or  clipped,  there 
are  no  green  heads  in  which  the  midges  can  lay  their  eggs  the 
last  of  May. 

If  the  hay  crop  has  been  cut  before  June  20,  the  larvae  are 
still  in  the  clover  heads,  and  are  killed  by  the  drying  of  the  hay; 
so  there  will  be  no  flies  to  lay  their  eggs  on  the  young  heads  of  the 
seed  crop.  If  the  hay  crop  is  not  cut  until  July,  the  larvae  will 
have  gone  into  the  ground  by  that  time,  and  there  will  be  an 
abundance  of  flies  in  August  to  lay  their  eggs  on  the  seed  crop. 

The  flies  that  emerge  from  the  ground  during  the  last  of  May 
are  from  larvae  that  have  passed  the  winter  in  the  clover  field 
on  the  roots  of  the  plants.  These  larvae  are  from  eggs  laid  the 
preceding  autumn  on  green  heads  that  formed  during  the  first 
year  of  the  clover’s  growth.  It  is  evident,  therefore,  that  the 
clover  should  be  prevented  from  forming  heads  in  its  first  year, 
and  that  these  heads,  if  formed,  should  be  destroyed  by  cutting, 
as  in  method  No.  4. 

Volunteer  clover  should  be  destroyed  because  it  harbors  the 
clover  pests,  affording  them  food  at  times  when  the  cultivated 
clover  is  not  available. 

Seed-chalcid 

Bruchophagus  funebris  How. 

Adults  of  first  generation  most  abundant  about  the  middle 
of  June,  laying  eggs  in  flowers  that  have  been  fertilized  and 
have  begun  to  wither;  never  in  green  heads  or  in  seeds  that  are 
hard.  Characters  of  the  adult  chalcids;  habits,  including  ovi¬ 
position.  The  egg.  The  larva  eats  out  the  inside  of  a  develop¬ 
ing  seed.  Infested  seed  compared  with  healthy  seed.  The  adult 
eats  its  way  out,  leaving  only  the  shell  of  the  seed.  Most  of 
these  empty  shells  are  blown  away  with  the  chaff,  when  the  seed 


26 


is  hulled;  a  few  are  carried  over  with  the  sound  seed.  An  im¬ 
mense  loss  of  seed  is  due  to  this  pest,  the  presence  of  which  is 
unsuspected  by  most  farmers.  The  second  generation  of  adults 
is  most  abundant  in  the  middle  of  August  and  lays  eggs  on  the 
seed  crop.  The  third  generation  occurs  in  autumn,  and  oviposits 
in  premature  heads  of  first-year  clover,  also  in  volunteer  clover, 
The  insect  passes  the  winter  inside  the  seed,  on  the  ground, 
chiefly  as  a  larva. 

Control. — Use  the  methods  already  given.  If  the  clover  has 
been  pastured  or  clipped,  there  will  be  no  heads  for  the  chalcids 
to  lay  their  eggs  in,  in  the  middle  of  June;  consequently  no 
second  generation  will  develop  in  that  field  to  infest  the  seed 
crop,  the  chalcids  entering  from  other  fields  being  few  in  num¬ 
ber.  If  the  hay  crop  is  cut  when  fresh  in  bloom,  the  crop  is 
taken  out  of  the  reach  of  the  chalcid,  and  the  second  generation 
prevented  from  developing  in  that  field.  The  June  chalcids  in 
a  field  are  from  eggs  laid  in  premature  heads  in  the  same  field 
the  preceding  autumn.  Thus  the  importance  of  Rule  No.  4  is 
evident. 

Glover  Seed-caterpillar 
Enarmonia  inter stinctana  Clem. 

The  adults  are  small  brown  moths  with  silvery  markings. 
They  are  most  abundant  when  green  clover-heads  are  most  nu¬ 
merous,  laying  their  eggs  in  these.  Thus  the  periods  of  maximum 
abundance  coincide  with  those  of  the  seed-midge.  First  gen¬ 
eration  of  moths  most  abundant  in  the  last  of  May;  second,  late 
in  July;  third,  late  in  August  and  early  in  September.  Appear¬ 
ance  of  infested  clover-heads;  the  caterpillar  eats  out  the  bases 
of  the  florets;  characters  of  the  caterpillar.  Winter  is  passed 
chiefly  in  the  pupal  stage;  sometimes  in  the  larval  stage. 

Control. — Use  the  same  methods  as  for  seed-midge  and  seed- 
chalcid. 

Reference  on  Clover  Insects. — Bull.  134,  Illinois  Experiment 
Station.  This  contains  many  references  on  the  subject. 

TRANSMISSION  OF  DISEASES  BY  INSECTS 

Present  importance  of  the  subject. 

Malaria 

Laveran,  1880.  Development  of  Plasmodium  in  erythrocytes. 
Terms  used:  schizont,  melanin,  merozoite,  gametes,  macro- 


27 


gamete,  microgametocyte,  microgamete,  ookinete,  oocyst,  sporo- 
blast,  sporozoite.  Types  of  malaria:  tertian,  quartan,  aestivo- 
autumnal.  Effects  of  the  disease  on  the  human  system.  Experi¬ 
ments  proving  the  transmission  of  malaria  by  mosquitoes  of  the 
genus  Anopheles.  Comparison  of  Culex  and  Anopheles  in  their 
several  stages.  Preventive  measures. 

Yellow  Fever 

Historic  account.  The  disease  not  understood  until  1900. 
Pioneer  work  of  Dr.  Charles  J.  Finlay.  The  U.  S.  Yellow  Fever 
Commision:  Major  Walter  Reed,  Dr.  James  Carroll,  Dr.  Jesse  W. 
Lazear,  Dr.  A.  Agramonte.  Brilliant  work  of  this  Commission 
in  Cuba  in  1900.  The  harmlessness  of  fomites.  Transmission  of 
yellow  fever  by  the  transfusion  of  human  blood.  Experiments 
that  prove  that  the  disease  is  transmitted  solely  by  a  mosquito, 
Aedes  calopus  ( Stegomyia  fasciata).  Influence  of  climate  and 
season  upon  the  habits  of  this  mosquito.  The  specific  cause  of  yel¬ 
low  fever  is  as  yet  undetected.  Control  of  the  disease  in  Havana 
by  Major  W.  C.  Gorgas.  Yellow  fever  in  New  Orleans.  Control 
of  fever  in  the  Canal  Zone  by  Col.  Gorgas. 

Typhoid  Fever 

Transmission  of  Bacillus  typhosus.  Infection  of  water, 
milk,  etc.  Agents  of  transmission.  Proof  that  the  disease  may 
be  transmitted  by  flies,  particularly  Musca  domestica.  Habits 
and  life  history  of  the  house-fly.  Methods  of  control.  Other  in¬ 
testinal  diseases  transmitted  by  flies. 

Plague 

History  of  the  disease.  Three  types:  bubonic,  septicaemic, 
pneumonic.  Primarily  a  disease  of  rats,  transmitted  among  rats 
and  to  man  by  several  species  of  fleas.  Experiments  that  prove 
this.  Plague  in  San  Francisco;  its  suppression  by  Dr.  Rupert 
Blue.  Transmission  by  ground-squirrels. 

Trypanosomiases 

Structure  of  a  typical  trypanosome.  The  hosts  of  trypano¬ 
somes.  Tsetse  flies.  Nagana.  Bruce’s  experiments  on  nagana, 
which  is  caused  by  Trypanosoma  brucei  and  carried  by  Glossina 
morsitans  chiefly.  Preventive  measures.  Human  trypanoso¬ 
miasis  ;  symptoms,  mortality.  T.  gambiense  and  G.  palpalis.  Pre¬ 
vention. 


28 


Filariasis 

Studies  by  Manson,  Bancroft,  and  others.  Habits  of  Filaria 
bancrofti.  Transmission  by  Culex.  Effects  on  the  human  sys¬ 
tem. 

Other  Diseases 

Cholera  transmitted  by  flies.  Dysentery  also.  Tuberculosis 
possibly,  under  certain  conditions.  Ophthalmia.  Dengue.  Kala- 
azar.  Researches  on  Simulium  in  relation  to  pellagra.  Investi¬ 
gations  of  Rosenau  and  Brues  on  the  transmission  of  poliomyel¬ 
itis  (infantile  paralysis)  by  the  stable-fly  ( Stomoxys  calcitrans). 

References 

Howard. — Mosquitoes.  New  York;  McClure,  Phillips,  &  Go. 
Howard. — Yearbook,  U.  S.  Dept.  Agr.,  1901. 

Braun. — The  Animal  Parasites  of  Man.  New  York:  Lea 
Bros.  &  Co.  r 

Osier. — Modern  Medicine.  Phila.  and  New  York:  Lea  Bros. 
&  Co. 

Calkins. — Protozoology.  New  York  and  Phila. :  Lea  &  Febi- 

ger. 

Riley  &  Johannsen. — Handbook  of  Medical  Entomology. 
Ithaca,  N.  Y. :  Comstock  Pub.  Go. 

Doane. — Insects  and  Disease.  New  York:  Henry  Holt  &  Co. 
Howard. — The  House-fly.  New  York:  F.  A.  Stokes  Co. 

BOOKS  ON  ECONOMIC  ENTOMOLOGY 

Insect  Pests  of  Farm,  Garden  and  Orchard.  E.  D.  Sanderson. 
John  Wiley  &  Sons,  New  York. 

Insects  Injurious  to  Staple  Crops.  E.  D.  Sanderson.  John 
Wiley  &  Sons,  New  York. 

Injurious  Insects.  W.  G.  O’Kane.  Macmillan  Go.,  New  York. 
Economic  Entomology.  J.  B.  Smith.  J.  B.  Lippincott  Co., 
Philadelphia. 

Manual  of  Fruit  Insects.  M.  V.  Slingerland  and  C.  R.  Crosby. 
Macmillan  Go.,  New  York. 

Insects  Injurious  to  Vegetables.  F.  H.  Chittenden.  Orange 
Judd  Go.,  New  York. 

Insects  Injurious  to  the  Household  and  Annoying  to  Man. 
G.  W.  Herrick.  Macmillan  Go.,  New  York. 

The  Spraying  of  Plants.  E.  G.  Lodeman.  Macmillan  Co., 
New  York. 


29 


Most  of  the  literature  on  the  economic  entomology  of  the 
United  States  is  contained  in  the  following  serial  publications: 
Bulletins  of  the  U.  S.  Bureau  of  Entomology;  Reports  of  State 
and  of  Government  Entomologists;  Bulletins  and  Reports  of  the 
State  Experiment  Stations ;  Insect  Life;  The  Journal  of  Economic 
Entomology. 


